Constant velocity joint



April 30, 1946.

R. B. RANSOM 2,399,293

CONSTANT VELOCITY JOINT Filed July 8; 1945 j is I N VEN TOR.

Patented Apr. 30, 1946 CONSTANT VELOCITY JOINT Application July 8, 1943,Serial No. 493,873

4 Claims. (Cl. 642 1) Ihe invention relates to universal joints and ithas particular relation to a universal joint of constant velocitycharacter. In certain respects, the invention constitutes an improvementover that embodied in my copending application for patent, Serial No.80,490, filed March 25, 1943.

One object of the present invention is to provide an improved type ofconstant velocity universal joint wherein torque loads are imparted fromone shaft to another through the use of an intermediate or connectingmember in the form of a single pin or trunnion element extendingdiametrically through the joint center.

Another object of the invention is to provide a universal point ofconstant velocity character which is simple and wherein very few partsare required.

Other objects of the invention will become apparent from the followingspecification, the drawing relating thereto, and from the claimshereinafter set forth.

For a better understanding of the invention, reference may be had to theaccompanying drawing, wherein:

Figure 1 is a side elevational view of a universal joint constructedaccording to one form of the invention;

Figure 2 is a cross-sectional view taken substantially along the line 22of Figure 1;

Figure 3 is a plan view of the structure shown by Figure 1;

Figure 4 is a geometrical diagram illustrating the manner in whichconstant velocity action is obtained; and

Figure 5 is a view on the order of Figure 2, illustrating another formof the invention.

Referring to Figures 1 and 2, a shaft element H) is shown and thiselement has a three-arm yoke element thereon with the arms indicated ati2, i3, and M. A second shaft element l6 also has a three-arm yokeelement I l and the arms of this element are indicated at l8, l9, and20. All of the arms are disposed in circumferentially alternatingrelation and are sufnciently separated one from another to permit normaljoint operation.

An intermediate or connectin member comprises a pin 23 having reducedend portions 24 and 25 which receive rollers 25 and 21. The roller 26includes an imler cylindrical portion 23 and a frusto-conical outerportion'29, and the roller 21 similarly includes a cylindrical innerportion 32 and a frusto-conical outer portion 33. For holding therollers in position, collars 34 and 35 may be provided on thereducedportions 24 and of the pin and the ends of the pin are threaded and haveretainin nuts 3? and 38 for holding the parts together. This arrangementenables locating the rollers accurately in position so that the yokeelement It has a long flat surface 43 which substantially has linecontact with the upper side of the pin between the cylindrical portions23 and 32 of the rollers. It will be noted that this third arm has asubstantially long line of contact and that this line of contact extendssubstantially on each side of the axial center of the pin. If the yokeelement II is turned clockwise as seen in Figure 2, the surface 49 onarm It will drive arm 13 through the roller 28 and that portion of thesurface 33 on arm M to the right of the pin center will drive arm 20through the pin. These two lines of contact thus will impart motion tothe pin in the clockwise direction. If the element II is turnedcounterclockwise, the surface it on arm [3 will drive arm l8 throughroller 21 while that portion of surface 43 on arm M to the left of thepin center will drive arm 29 through the left side of the pin.

Arms I8 and it on element ll similarly have flat surfaces and 46substantially contacting the cylindrical portions 28 and 32 of therollers at the upper side of the pin, while the third arm 2% has a longfiat surface 47 substantially contacting the pin oppositely to thesurface M on arm It. If the shaft element I! is turning counterclockwiseas seen in Figure 2, rotation of the shaft element II is effectedthrough engagement of the same surfaces as when shaft element H isturning clockwise, but the movements will be reversed. If the shaftelement I7 is driving clockwise, arm l8 drives arm 13 through roller 21While the left side of arm 2% drives the left side of arm l4 through thepin.

In order to obtain constant velocity, the arms i2 and i9, respectively,have surfaces 59 and 5! adapted to contact the under side of thefrustoconical portion 29 of roller 28. These surfaces 50 and El areinclined to the pin axis and are curved axially of the arms. Similarly,the arms I3 and it have inclined surfaces 52 and 53 which I curvedaxially of the axis of shaft element 18 with curvatures correspondingrespectively to portions RzRi ofthe two Archimedes spirals M, M1 shownin Figure 4. This means that each of the surfaces comprises a serial ofprogressively larger spirals so as to form the full inclined surface andthat along any axial section, the curve at the section line.willcorrespond to a spiral. Similarly, the surfaces 5| and 53 on arm l9 andI8 of yoke element 11 are curved axially in accordance with portions$281 of Archimedes spirals N, N1. The spirals M, Mi are centered at 0,while the spirals N, N1 are centered at the point 02 with such centersequally spaced from the joint center 0. These centers are on the axis ofshaft elements l and "5, respectively, and hence during any angling ofeither shaft about the joint center 0, the center of the spiral shiftsalso about the joint center 0.

If the shaft IUis swung through the angle o, the spiral M and M1 swingalso through that angle to the dotted line positions shown. Theintersections A and A1 of thespirals which were on a normal to the shaftaxes when the latter were aligned, now shift to points C and B, but theline CB1 has only shifted through half the angle Rollers in contact withthe spiral surfaces hence will shift through half the shaft an le andaccordingly the axis of the driving pin will shift from AA1 to C131 andwill bisect the shaft angle so as to obtain constant velocity.

A more complete and detailed description of the manner in which the pinaxis is shifted into the angle bisecting position may be found in thecopending case identified, and attention is directed to that caseaccordingly. It may be observed generally, however, that other spiralsor curved surfaces may be used in place of the particular spiralmentioned and that each conical roller will not contact the surfaces onthe line of bisection, but will contact such surfaces at points spacedsubstantially equally from the line of bisection.

It will be appreciated in the joint described that the surfaces 50, 52,and 53 are so related that the arms on the yoke elements can not bepulled axially apart owing to the spiral surface on each arm risingbeyond the roller. In other words, to pull either shaft element axiallyfrom the other would require that the rising end of the curved surfacebe pulled under the conical roller surface. Axial movement of the shaftelements in the other direction is prevented by hearing elements 12 and13 which are located respectively in openings 14 and 15 extendingthrough the arms 20 and M. The bearing elements 12 and 13 havecylindrical seats 16 and H substantially fitting the central portion ofthe pin, and such bearing elements may turn in the openings 14 and 15about their own axis as may be required. For holding the bearingelements positioned, plugs 19 and 80 are threaded into the outer ends ofthe openings 14 and 15.

These bearing elements and the curved surfaces 50, 5|, 52, and 53co-operating with the conical rollers on the pin act to center the partsat a joint center 0 in Fig. 4 about which all pivotal movement occurs.Additionally, the shaft elements have spherical interfitting casingelements l0 and H movable one Within the other and centered at O withthe element H including a separable part I2 for permitting assembly.These casing elements act also to locate the joint center and provide agrease or lubricant container for lubricating the joint.

In another form of the invention shown by Fig. 5, the spirally curvedsurfaces are reversed so that surfaces 59 and 52, instead of being onarms 12 and I3, are on arms [9 and I8, and surfaces 5| and 53 are onarms 2 and i3. In other words, the surfaces on arms l2 and I3 correspondto spiral portions S251 while the surfaces on arms 19 and i8 correspondto spiral portions R2Rl. With the surfaces so arranged, pulling apart ofthe arms axially is not prevented by such surfaces, and accordinglyaxial assembly and disassembly of the pin rollers and arms is permitted.This enables making the pin and rollers integral as shown so that thejoint proper requires only three pieces, namely, the two yoke elementsand the pin.

In centering the joint 0 it will be first seen that the spiral surfacesprevent movement of the arms axially inward past the position Where theyare in contact with the conical surfaces. Movement of the arms axiallyapart may be accomplished by using housing elements such as the elements'10 and H in Fig. 1. In this case the bearing elements l2 and 13 areeliminated, and this enables attaining a stronger third yoke arm and agreater length of direct load contact between the arm and pm.

While more than one form of the invention has been illustrated anddescribed in detail, it will be apparent to those skilled in the artthat various modifications may be made without departing from the scopeof the appended claims.

What is claimed is:

l. A constant velocity universal joint comprising a pair of shaftelements, a diametrically extending pin, a pair of axial arms on oneelement extending past the pin at one side and substantially contactingthe pin adjacent its ends respectively, a third axial arm on the oneelement and extending past the pin at the opposite side andsubstantially contacting it intermediate its ends, a second pair of armson the other element and extending past the pin at said opposite sideand substantially contacting the pin adjacent its ends, and a third armon said other element extending past said one side of the pin andsubstantially contacting it intermediate its ends, and means at theouter ends of the pin for moving it into a position where its axissubstantially bisects the angle between the shafts when either shaft isangled relative to the other.

2. A constant velocity universal joint comprising a pair of shaftelements, a diametrically extending pin, a pair of axial arms on oneelement extending past the pin at one side and substantially contactingthe pin adjacent its ends respectively, a third axial arm on the oneelement and extending past the pin at the opposite side andsubstantially contacting it intermediate its ends, a second pair of armson the other element and extending past the pin at said opposite sideand substantially contacting the pin adjacent its ends, and a third armon said other element extending past said one side of the pin andsubstantially contacting it intermediate its ends, and means at theouter ends of the pin for moving it into a position where its axissubstantially bisects the angle between the shafts when either shaft isangled relative to the other, said means comprisg urved surfaces on thearms at each end of the pin and overhanging surfaces on the pin engagingthe curved surfaces.

3. A constant velocity joint comprising a pair of shaft elements, adiametrically extending pin having frusto-conical collars on its ends, apair of axial arms on one element extending past the pin at one side andsubstantially contacting the pin adjacent its ends, said arms havingsurfaces inclined to the pin axis and curved longitudinally of the armsand contacting the collar, a third axial arm on the one element andextending past the pin at the opposite side and substantially contactingit intermediate its ends, a second pair of arms on the other element andextending past the pin at said opposite side and substantiallycontacting the pin adjacent its ends, said second pair of arms havingsurfaces inclined to the pin axis and curved longitudinally of the armsand contacting the frusto-conical surface of the collar, and a thirdaxial arm on said other element and extending past the pin at said oneside nd substantially contacting it intermediate its ends.

4. A constant velocity joint comprising a pair of shaft elements, adiametrically extending pin having frusto-conical collars on its ends, apair of axial arms on one element extending past the pin at one side andsubstantially contacting the pin adjacent its ends, said arms havingsurfaces inclined to the pin axis and curved longitudinally of the armsand contacting the collars, a third axial arm on the one element andextending past the pin at the opposite side and substantially contactingit intermediate its ends, a second pair of arms on the other element andextending past the pin at said opposite side and substantiallycontacting the pin adjacent its ends, said second pair of arms havingsurfaces inclined to the pin axis and curved longitudinally of the armsand contacting the frusto-conical surface of the collars, and a thirdaxial arm on said other element and extending past the pin at said oneside and substantially contacting it intermediate its ends, the curvedsurfaces on the arms of one element being substantially centered at apoint spaced from and at one side of the pin axis and the curvedsurfaces on the arms of the other element being centered at a pointspaced from the pin axis but at the side opposite the first centerRICHARD B. RANSOM.

